B, b&#39;, b&#34;-tris(pyridinium halide)- and b, b&#39;, b&#34;-tris(quinolinium halide)-borazines and a process for their preparation



3,052,686 Patented Sept. 4, 1962 This invention relates to newquaternary borazine salts and to the method of their preparation. In onespecific aspect, it relates to novel quaterary salts made by reacting aB-trihaloborazine with an azaaromatic heterocycle containing only oneannular nitrogen atom.

In recent years, there has been considerable interest in the artrelating to boron-nitrogen compounds, particularly those containing aborazine nucleus. B-trichloroborazine has become commercially availableand various substituted borazines derived therefrom have been found tobe useful as fuel additives, hydraulic fluids, and in the preparation ofoptical bleaches and antioxidants. Gould, in US. Patent 2,754,177,described and claimed a class of B-triaminoborazines, useful as fueladditives and for other purposes, made by reacting primary or secondaryamines with B-trihaloborazines. Turner et al., Chem. and Ind., page 526(1958) reported a reaction between boron trichloride-primary amineadducts and tertiary amines to form amino substituted borazines.

Quite surprisingly, in view of the teachings of prior workers, I havediscovered a new class of B-substituted borazines wherein one or more ofthe boron atoms of the borazine nucleus is attached to a quatennizednitrogen atom. My new compounds, which are the first known borazinescontaining an onium nitrogen, are useful dye intermediates in thepreparation of fiber reactive dyestuffs as explained in detail hereafterand, in addition, they are potent biocides. My novel quaternarystructure has a three-fold advantage over the parent borazine compounds,i.e. (1) greater dispersibility in water, (2) greater resistance tosolvolysis, especially hydrolysis, and (3) greater control of reactivityunder milder metathetical conditions.

It is therefore an object of the present invention to provide a uniqueclass of quaternary borazine salts and a method for their preparation.

In accordance with the invention, I have discovered novel quaternaryborazine salts characterized by the formula:

In the above formula at least one Z is the onium halide of a quaternizedazaaromatic containing only one annular nitrogen and from 5-10 carbonatoms. Those Zs not representing the quaternized azaaromatic, if any,are halogen and R is a member selected from the group consisting ofhydrogen, lower alkyl, aryl and substituted aryl, wherein thesubstituents afiixed to the aryl nucleus are members selected from thegroup consisting of nitro, halo and lower alkyl. The term onium halideof a quaternized azaa-rcmatic containing only one annular nitrogen andfrom 5-10 carbon atoms thus embraces the quaternary halide residues ofpyridine, lutidine, picoline, quinoline, isoquinoline, quinaldine, andthe like and could be represented by the following structural formulas:

wherein R is lower alkyl and X is halogen.

The compounds of the invention are made by reacting a B-trihaloborazineof the formula:

wherein R and X are as defined aforesaid with an azaaromatic heterocyclecontaining only one annular nitrogen atom and from 510 carbon atoms.Such azaaromatics include pyridine, quinoline, isoquinoline and thealkyl substituted pyridines, quinolines and isoquinolines.

The mole ratio of the reactants used in the new process depends on theparticular quaternized product desired. In order to obtain completesubstitution, at least 3 moles of azaaromatic are reacted with each moleof B-trihaloborazine. If only one mole of azaaromatic per mole ofB-trihaloborazine is used, the resulting product contains onequaternized substituent and two halo substituents attached to the boronatoms. Approximately one mole of azaaromatic per mole ofB-trihaloborazine should be used to obtain the maximum yield of themono-substituted quaternized product. There is no theoretical upperlimit on the amount of azaaromatic present, since a large excess thereofserves as a solvent for the reaction.

In addition to the use of excess azaaromatic heterocycle as a solvent,reaction is facilitated by the use of inert nonpolar solvents in whichthe borazi-ne is soluble and which do not react with the azaaromatic.Thus, suitable solvents include hydrocarbons, such as cyclohexane,heptane, and decane; aromatic hydrocarbons, such as benzene, toluene,and xylene; chlorinated hydrocarbons, such as trichlorobenzene,trichloroethylene and the like; nitro aromatics, such as nitrobenzene;ethers, such as ethyl ether, butyl ether, and dioxane; and amides, suchas dimethylformamide and the like.

I The temperature required for the reaction varies with the reactivityof the halogen atom afiixed to the B-trihaloborazine and also with theextent to which the reactant borazine is sterically hindered. Forexample, reac- 'tion between pyridine and B-tribromoborazine begins onadmixing the two materials at room temperature (ca. 25 C.). If, insteadof the B-tribromoborazine, a N-organo-B-trichloroborazine is used as thereactant,

there is little or no reaction below about 70 C. The upper temperaturelimit depends on the stability of the reactants and products. Generallyspeaking, temperatures up to about 200 C. are safe operatingtemperatures; thus, unless an extremely high boiling solvent is used,the reaction is most conveniently run at the reflux tempera ture of thereaction mixture.

From the standpoint of economy of operation, the reaction is preferablyconducted at atmospheric pressure. The use of vacuum is not helpful,although superatmospheric pressures can be used if desired. The higherpressures are sometimes useful in promoting reaction between theazaaromatic and the more sterically hindered borazmes.

The reaction time depends to a large extent upon the temperature chosen.At higher temperatures, some reaction occurs substantiallyinstantaneously, although it is best to provide a sufficient period oftime, for example, from about one to several hours, to permit thereaction to go to completion.

The product quaternary borazine salts are high melting solids which, incontrast with the parent borazines, are more readily water soluble andmore stable to hydrolysis. In general, the quaternary salts of theinvention are organic solvent insoluble. For this reason, the presenceof the inert non-polar solvent during the reaction facilitates productwork-up, since the desired product simply precipitates from solution andit is easily recovered by conventional separation techniques.

Consideration has been given by workers in the art to usingB-trihaloborazines as intermediates in the production of fiber reactivedyes. Unfortunately, they are not useful as such because of their watersensitivity and instability under alkaline conditions. Moreover, inattempts to fix the haloborazine nucleus to the cellulosic fiber, theacids produced by any reaction between the B-halo groups and the OH ofthe cellulose result in a tendering and an ultimate degradation of thefiber. Astonishingly, the quaternized borazines of the invention areremarkably effective as intermediates in the production of excellentfiber reactive dyestuffs. For example, useful dyestuffs are made bysubstituting one or two of the halo groups attached to the boron atomsof the borazine ring with a suitable chromophore, e.g. an aminoazodyestuff, and reacting the remaining halo groups with an azaaromaticaccording to the method of the invention to produce partiallyquaternized structures. As I have noted, the borazines containing anonium nitrogen are relatively stable to hydrolysis and, upon reactionwith the cellulose, the free amine produced neutralizes any acidreleased.

My novel compounds also possess remarkable biocidal properties, whichmake them useful in a variety of applications. For example, the newcompounds can be applied to paper from an aqueous dispersion of suitableconcentration. The treated paper is then air dried and baked at 100-105"C. for a short period of time to give a fixed grain, biocidal paperuniformly impregnated and resistant to water leaching.

My invention is further illustrated by the following examples:

Example I To a stirred solution of g. (0.032 mole) B-tribromoborazine in50 ml. substantially anhydrous benzene in a 100 ml. round bottom flaskwas added 8.3 g. (0.105 mole) substantially anhydrous pyridine. Afterthe addition of pyridine was complete, the resulting mixture wasrefluxed and thereafter cooled. The light gray product was easilyrecovered by filtration of the precipitate, followed by removal ofoccluded solvent and excess pyridine at reduced pressure. This product,in contrast with B-tribromoborazine, has greatly reducedwater-sensitivity and has the lack of definitive melting point which ischaracteristic for a quaternary compound. The product was identified byits gain in weight and infrared analysis, which indicated the followingstructural formula:

N: Br- 1'3 Br HN/ \NH Br- Example II A 250 ml. round bottom flask wascharged with 9 g. (0.0398 mole) N-trimethyl-B-trichloroborazine, 100 ml.cyclohexane, and 25 g. (0.31 mole) pyridine. A slight initial reactionoccurred, after which the mixture was refluxed for several hours. Thensolvent and excess pyridine were removed at reduced pressure to give13.6 g. product. This borazine had added 1.46 moles pyridine per mole ofborazine, thus representing .a mixture of partially quaternizedproducts, i.e.:

(Ill B CH Example 111 The procedure of Example II was substantiallyrepeated, using N-tri-mnitrophenyl-B-trichloroborazine, 10 g. (0.0183mole), as the azaaromatic reactant. After removal of solvent and excesspyridine, 13.7 g. product was recovered, indicating reaction of 3.7 g.(0.0465 mole) pyridine or 2.54 moles pyridine per mole of borazine. Theproduct, chemically, B,B'B"-tris(pyridiniumchloride)-N,N,N"-tris(m-nitrophenyl) borazine, was identified as in theprevious examples.

Example IV I claim: 1. A compound of the formula:

2 R1TT N-R ZB i3-z wherein Z is a member selected from the groupconsisting of quaternary ammonium halide residues of pyridine, picoline,lutidine, quinoline, isoquinoline, and quinaldine, the nitrogen atom ofsaid member being bonded directly to the boron atom, Z is a memberselected from the group consisting of halogen and Z, the nitrogen atomof said member being bonded directly to the boron atom, and R is amember selected from the group consisting of hydrogen, lower alkyl,phenyl and nitrophenyl.

2. B.B,B" tris (pyridinium chloride) N.N',N- tris-(in-nitrophenyl)borazine.

3. B-chloro-B,B-bis-(pyridinium chloride)-N,N',N- trimethyl-borazine.

4. B,B dichloro-Bpyridiniun1 chloride-N,N',N-trimethyl-borazine.

5. B,B',B-tris(pyridinium chloride) borazine.

6. B,B,B-tris(pyridiniurn bromide) borazine.

7. A method of making a quaternary ammonium borazine salt characterizedby the formula:

wherein Z is a member selected from the group consisting of thequaternary ammonium halide residues of pyridine, picoline, lutidine,quinoline, isoquinoline and quinaldine, the nitrogen atom of said memberbeing bonded directly to the boron atom, Z is a member selected from thegroup consisting of halogen and Z, the nitrogen atom of said memberbeing bonded directly to the boron atom, and R is a member selected fromthe group consisting of hydrogen, lower alkyl, phenyl and nitrophenyl,comprising reacting a compound of the formula:

is reacted with said azaaromatic heterocycle in an equimolar ratio.

9. Method according to claim 7 wherein said compound of the formula:

is reacted with said azaaromatic heterocycle in a 1:2 ratio,respectively.

10. Method according to claim 7 wherein said compound of the formula:

is reacted with said azaaromatic heterocycle in a 1:3 ratio,respectively.

No references cited.

1. A COMPOUND OF THE FORMULA:
 7. A METHOD OF MAKING A QUATERNARYAMMONIUM BORAZINE SALT CHARACTERIZED BY THE FORMULA